Boundaries, Eta Invariant and the Determinant Bundle
Boundaries, Eta Invariant and the Determinant Bundle
Cobordism invariance shows that the index, in K-theory, of a family of pseudodifferential operators on the boundary of a fibration vanishes if the symbol family extends to be elliptic across the whole fibration. For Dirac operators with spectral boundary condition, Dai and Freed [] gave an explicit version of this …